{ ... }:
{
  # This setups a SSH server. Very important if you're setting up a headless system.
  # Feel free to remove if you don't need it.
  services.openssh = {
    enable = true;
    settings = {
      # Require a ssh key login for root.
      PermitRootLogin = "prohibit-password";
      # Use keys only. Remove if you want to SSH using password (not recommended)
      PasswordAuthentication = true;
    };
  };
}